Terpene phenoxyacetate growth regulators



TERPENE PHENOXYACETATE GROWTH REGULATORS Charles F. Krewson, Abington,

Upper Darby, America as represented by the Secretary of Agriculture and Edward J. Saggese,

No Drawing. Application November 20, 1957 Serial No. 697,751

7 Claims. (Cl. 71- -2.6) (Granted under Title 35, S. Code (1952), sec. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power Pa., assignors to the United States of to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to herbicides, or weed killers,

especially mesquite killers, and to the selective control of plant growth. More particularly, this inventionrelates to the use of a group of compounds represented by the general formula phenoxy alkyl radical, as for example,-the radicals 4-chlorophenoxy, 2,4-dichlorophenoxy, :2,4,S-trichlorophenoxy, 2-methyl-4-chlorophenoxy, and 2,4-dichlorophenoxyethyl.

An object of this invention is to provide stable herbicidal compounds that may be formulated and applied by conventional procedures. invention is to provide compounds which when properly Patented Jan. .13, 1959 Nopol I1) 1- [6,6-dimethylbicyclo- (1,1,3 -liept-2-en-2y1]-ethan-2-o1 I ona-o-o-onion on CH3 a-Terpinyl ethylene glycol ether (III) In the practice of this invention the terpene compounds, hydronopol, nopol, and terpinyl ethylene glycol ether werepacylated with nuclearly chlorinated phenoxy alkyl acidssuch as 4-chlorophenoxyacetic acid, 2-methyl-4 chlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, 2-(2,4--dichlorophenoxy)propionic acid, 4-(2,4-dichlorophenoxy)butyric acid,

and DL-2-(2,4,5-trichlorophenoxy)propionic.acid to produce the corresponding terpene derivatives.

Another object of the present 3 t formulated and applied have herbicidal activity against mesquite. A further object is to provide compounds which will retard growth or kill mesquite without adversely,

affecting the growth of a desired plant species. Still another ,object of the present invention is to provide herbicides of exceptionally low volatility, thereby preventing winddrift and theresulting damage to plants for which the herbicide was not intended.

We have discovered that a group of terpene derivatives of nuclearly chlorinated phenoxy acids arecompounds,

which meet the objective of very low volatility and which have desirable herbicidal properties. For example, certain compounds in this group are especially effective herbicides for mesquite. Other compounds are selective herbicides for killing weeds (including undesired crops), in lespedeza or oats. While especially valuable as postemergent herbicides, for either complete or selective herbicidal activity, these terpene derivatives"1 also appear particularly useful as pre-emergence treatments for certain crops. q

The terpene compounds converted to the herbicides of the present invention are readily available as products of the Naval Stores industry and are known in the trade as hydronopol (I), nopol (II). and terpinyl ethylene glycol,

ether (III). These compounds are described by the following structures: i

The descriptions which follow are given to illustrate the procedures employed in the preparation of the terpene esters. Ingeneral, the hydronopol derivatives were made by using azeotropic dehydration techniques and the nopol 1 derivatives by using Schotten-Baurnann procedures. Subwherein A is a terpene radical such as nopyl, hydronopyl, and a-terpinyloxyethyl, R is H or CH and R is a' nuclearly chlorinated phenoxy ornuclearly chlorinated sequently, after completing this series of nopol esters it be preparedazeotropically in xylene or benzene with or without the use of catalysts. However, the a'ze'otropic" technique as-amethocl of preparing nopol esters-had at first been abandoned because these compounds were eX-,

pected to be crystalline following the pattern of the first two terpene esters prepared, hydronopyl 4-chlor'oand q hydronopoyl-2,4,S-triChlorophenoxyaeetate. With the exception of 2-m'ethyl 4-chlorophenoxyacetic acid which was purified by recrystallization from benzene,

the halogenated phenoxy acids and the terpene com- 7 pounds were technical grades and were used without purification.

EXAMPLE 1' furic acid. This mixture wasr'efiuxed 7 hours, the theoretical amount of water being collected within this time i in an attached moisture tube. mixture was washed successively When cool the reaction bonate solution and distilled water. The solvent was stripped off and the product, 2093 grams (86% yield) 1 was purified by two recrystallizations from petroleum ether to give 1825 grams (75% yield) of hydronopyl- 2,4,5 trichlorophenoxyacetate, M. P, 5556 C. The

latter yield is lower than need be because no attempt was made to recover additional product from mother liquors.

Data pertaining to hydronopyl-2,4,5-trichlorophenoxy acetate are presented in Table I.

EXAMPLE 2 propriate starting materials, hydronopyl-4-chlorophenoxy same procedures as described in Example 1.

EXAMPLE 3 42.1 grams (0.25 mole) of hydronopyl dissolved in 200 with dilute sodium car- 7 m1. xylene was added 56.8 grams (0.25 mole) of DL-2- (2,4-dichlorophenoxy)propionic acid and 0.5 ml. sulfuric acid. This mixture was refluxed for 10 hours, sufficient time for the collection of the theoretical amount of water in an attached moisture tube. Acid was removed by washing, as described in Example v1. .1'I.l1e solvent was stripped off and the resulting product, 85 grams (88.3% yield) was distilled under vacuum." A center cut of 69.3 grams of hydronopyl-2-(2,4-dichlorophnoxy)propionate, boiling at 206-208" C. at 2 rn'mwHg pressure, was collected for incorporation intog'r'owth regulator formulations 'This"compound a'nte'rewia- Table I"as'Example 3.

EXAMPLES 8 TO 12 Compounds listed in Table I as Examples 8 to 12 were prepared and purified by the procedures described in Example 7. p

EXAMPLE 13 2 (a 'terpiriyloxyethyl) 4 chlorophenoxyacetate.-- To terpinyl ethylene glycol ether, 19.8 grams (0.1 mole) in sodiumhydroxide solution (100 ml., 1 N) at C.

ableL-Rhysica an analyt l data on lemme de ve tives of aryloqcyalkylcarboxylic acids MPLES 4 v .wwtq -k-The' w t lp ep d y I es described injExample 3 and dataconcernpcu'ndsj afi pi j jsehtediin TablelI.

EXAMPLE 7 Nopyl==bhlorophergbryqcatata l$lopoL 16.1 grams cessively with dilute hydrochloric acid, sodium carbonate solution, and water. Removal "of the benzene from the washed solution gave an-oilwitha stron'g odor 'ofznbpbl The unreacted nopol was, removed from theizprodudtzhy. means 'of. steam distillation. Extraction with ether (3. times With 100 m e h rl qllowield by'...dr.ying underi-vacuum at C. gave 27.6 grams (82.5% yield) of nopyl- 4-chlorophenoxyacetate. Thi.s ."product was vacuum distilled and the fraction boiling at 1 177149 at rmi l t at 0.71am. Hgpr'essur'e'.

The low-volatile compounds described in Examples Chlorine Analysis, Example M. P., 0. (Com) or,v .Yleld, Percent No. Name 13. P., C. (Uncom) no .Berc'ent Oalcd. .Found 1 Hydronopyl 2,4,5 trichlOrO- B 1.5319 86.0 26. 22 25. 66

- phenoxyacetate. i 2.; Hydronopyl 4 chlorophen- 45.5-46.0 1. 5137 54.2 10.53 10. 87

oxyacetate; I v v 3 Hydronopyl 2 (2. 1-d1chlor0- 206-208 8412 11m; 1. 5265 88. 3 18. 40 18. 39

' pheno'xw propionate. f 4. Hydronopyl 4 (2,4-dlchl0ro- 198- 200 at 0.3111111--." 1. 529B 97. 2 17. 76 17. 85

I pheuoxy)butyrate. 1 I 5. -Hydi'o'nopyl -"2,4"-dich1or'o- 206-208 at'1.2mm- 1.5358 86.3 19.10 19. 09

phenoxyacetate. i Hydronopyl a -,methyl 4 188-190a1; 0.5mm".-- .1. 5239 15.4 10.10 10. 0a clilbrophenoxyacetdte'.

r --ch1 0rophenoxyaee- 147-149 at 0.05.mn1 1. 5322 182. 6 10. 558 E 10. 54 a e. v p 1 1 Nbpyl ,4-dlch1orophen0xy- 180-182 at'0.'06mm 1.6399 57.3 19.10 19.37 -::acetate' 5? i I 7 Nbp'yfl "-2 ,4 ,5 trichlorophen- 137-189 at 0.5 mm.. 1. 5490 53.0 26.34 26.43. ox'yacctatel 4 10 'Nopyl '2- methyl 4 chlorq: 163-165 at 0.1 111mm..- 1. 5292 25.0 1 10.10 10-73.

phenoxyacetate. f

11 'N' pyl 2 (ZA-dichlorophgn- 128430-1152] mmn. 1. 6310 7.6.1 18.49 18.80 p v g I, .V 1 12 Nopyl-2-(2,4,5 '-t 11 183-185 a; 0.5 1 1.5420 2.6.3 25,46 .26, 40 o1y)Dr0Dl0t1'ate.-' 13 2 (a Terplr-l-yloxyethyl) 4' 158-160 at 0.6 mm... :1. 5212 '42. 1 91.66 9. 88

chlorophenoxyacetate.

an additional Zhours during which time it was allowed to. warm up to room temperature, andwas then extracted 3 times with chloroform. Thecombined'chl'oroforr'n extracts were successively washed with dilute hydroc'hloric acidf sodiu'm' bicarbonate solution, and distilled water. The product was recovered by evaporating off the 'chldrio} form' and remov'in'gthe unreact'ed 'terpene by steamdistillation. The crude product was taken up in chloroform and; dried thoroughly to' remove all water anjd chloroform. The resulting liquid was dissolved' in anhydrou s benzene andpa'ssedthrough a column'c'ontaining activated alumina. The benzene eluate was concentrated and vac; uum dried ajt'70 C. 'togive 8.4 'gramsf(.23"'l7 yield): of '2 .tipifiyl'oxycthyl) 4 chlbrophenoxyifcet 'b, i o

liquids. "These compounds r'riay be {readily formulated; and appliedbyconventional procedures. "Some examples of thefapplica'tion of these compounds follow.

EXAMPLE 14 The compounds of Examples 1,-9and-12 were evaluated as herbicides using 2,4,S-trichlofophenoiyacetic acid, the propylene glycol butyl ether ester of"2,4,5-trichlorophenoxyacetic acid (2,4;5-TQPGBE) and"'2-(2,4,5-trich10rophenoxy)propionic acid as controls. "Aqueous 25% etha- -nol solutions containing 100 pl p. -m. of 2,4,5-trichloropheuoxyacetic acid orpthis acideguivalent of the other compounds, were prepared. Eight month old mesquite seedlings were dipped into one of the solutions, 25 replicates per solution, and the excess solution was allowed to drain 01f. Herbicidal effects, as determined at the end of 40 days, are recorder in Table II.

Table II.-Response after 40 days to treatment described in Example 14 of 8 month old mesquite seedlings Plants Stem Name Killed, Tissue Percent Killed,

Percent 2,4,5-Trichlorophenoxyacetic acid .1 21 83 2, 4,5 1, PGBE -1 33 94 Hydronopyl-2,4 5trich10r0phenoxyacetate r 46 94 Nopyl-2,4,5-tric lorophenoxyacetate 5O 92 2-(2,4,5-Trichlorophenoxy)propionlc acid 19 S2 N0pyl-2- (2,4,fi-trichlorophenoxy)proplonate 10 89 EXAMPLE Aqueous ethanol solutions of the compounds of Examples 1, 2, 3, S, 6, 7, 8, 9, 10, 11 and 13 were pre- Cit The results of Examples 14 and 15 show that the nopyl and hydronopyl esters of 2,4,5-trichlorophenoxyacetic acid are exceptionally effective herbicides for mesquite. Although the cited terpene derivatives of the other chlo' rinated phenoxy acids, as in Table III, were less effective than the nopyl and hydronoply esters of 2,4,5-trichlo rophenoxyacetic acid they were generally as effective or more effective, than the parent chlorinated phenoxy acids of which they were derivatives.

EXAMPLE 16 Post-emergence tests were conducted on several plant species. Healthy, young plants were sprayed with an Table I V.-Elfect of terpene derivatives on plants when applied as foliage sprays at rate of one pound acid equivalent per acre Percentage Reduction in Green Weight Yield Example No. Name White Red Al- Sweet Lespe- Soy- Cueum- Ra e Mus-- Pig- Lambs- Oats Glover Clover falfa Clover deza .beans ber p tard weed quarters Hydronopyl-ZA,5-trieh1orophenoxyaeetate 100 100 98 98 100 100 100 100 94 100 100 15 Hydronopyl-4-ehlorn pheno xyacetate 95 94 83 7 4 100 100 100 100 100 96 100 23 Hydronopyl-2-(2,4-dlchlorophenoxy)propionate... 100 96 95 97 O 81 100 100 100 83 92 9 Hydronopyl-ti-(2,4-dichlorophenoxy)butyrate-.. 18 16 41 0 59 54 97 69 100 91 5 Hydronopyl-2,4-dichlorophenoxyaeetate 100 100 100 100 100 100 87 100 100 100 100 15 Hydronopyl-2-methylt-chlorophenoxyacetate. 100 55 100 100 86 100 100 100 100 100 100 0 Nopyl-2,4-diehlorophenoxyacetate 100 100 100 100 100 100 93 100 100 100 100 19 N0pyl-2,4,5-trlchlorophenoxyacetate 100 100 98 95 100 100 100 98 100 100 100 15 Nopyl-2-methyl-4'chlorophenoxyacetatea 99 87 98 78 100 100 100 100 100 100 100 0 Nopyl-2-(2,4-diehlorophenoxy)propinnate. 94 99 95 100 0 85 100 99 98 100 86 12 Nopyl-2-(2,4,5-trichlorophenoxy)propionat 100 100 95 98 100 100 100 98 100 100 100 16 2,4 5 Trichlorophenoxyacetlc acid--.. 100 100 93 100 100 100 98 100 95 100 7 D -2-(2,4-dichlorophenoxy)propionic 99 90 91 97 100 99 100 109 97 99 85 0 4-(2,4-Dichlorophenoxy) butyric acid.. 10 16 86 36 69 41 100 78 100 14 2,4-Dichlorophenoxyacetic acid"... 99 100 100 100 100 100 87 100 100 100 100 15 2-Methyl-4-chlorophenoxyacetie acid. 100 65 100 100 100 100 95 100 100 100 100 3 Check 0 0 0 0 0 0 0 0 0 0 0 pared. These solutions contained a weight of terpene We claim:

Table III.-Efiect of aqueous 25% solutions of various compounds upon leaf drop of 8 month old mesquite Name Leaf Kill,

Percent Hydrono'pyl-ZA,5-trichlorophenoxyacetate Nopyl-2,4,5 trichlorophenoxyacetate Propglene glycol butyl ester of 2,4,5-trichlor 2,4,5-Triehlorophenoxyacetic acid Hydronopyl-2-methyl-4-chlorophenoxyacetate Nopyl-2methy1-4-eh1orophenoxyacetate a. Hydronopyl2-(2,4'dichlorophenoxy)propionate. Nopyl-2(2,4-dieh10rophenoxy)propionate 2,4-Diehlorophenoxyacetic acid Hydronopyl-2,4-dlchlorophenoxyaeetate-. NopyI-QA-dichlorophenoxyaeetate a- -(lhlorophenoxyaeetic acid a HydronopyM-chlorophenoxyacetate Nopyl-t-chlorophenoxyacetate 2-(a-Terpinyloxyethyl)4-ehl0rophenoxyacetate 1. The process of killing mesquite comprising contacting the mesquite plant with a phytotoxic concentration of a compound represented by the general formula AOCCHR I wherein A is a terpene radical selected from the group consisting of nopyl, hydronopyl and a-terpinyloxyethyl, R is selected from the group consisting of H and CH and R is selected from the group consisting of 4-chlorophenoxy, 2,4,-dichlorophenoxy, 2,4,5-trichlorophenoxy, 2-methyl-4-chlorophenoxy, and 2,4-dichlorophenoxyethyl.

2. The process of claim 1 in which the compound is n0pyl-2,4,5-trichlorophenoxyacetate.

3. The process of claim 1 in which the compound is hydronopyl-2,4,5-trichlorophenoxyacetate.

4. The process of claim 1 in which the compound is nopyl-Z- (2,4-dichlorophenoxy) propionate.

5. The process of claim 1 in which the compound is hydronopyl-Z-(2,4'dichlorophenoxy) propionate.

6. The process of claim 1 in which the compound is nopyl-2-methyl-4-chlorophenoxyacetate.

7. The process of claim 1 in which the compound is hydronopyl-2-methyl-4-chlorophenoxyacetate.

References Cited in the file of this patent UNITED STATES PATENTS 

1. THE PROCESS OF KILLING MESQUITE COMPRISING CONTACTING THE MESQUITE PLANT WITH A PHYTOTOXIC CONCENTRATION OF A COMPOUND REPRESENTED BY THE GENERAL FORMULA 